It is an important technique in biological and medical analyses to separate and recover a specific cell in a culture solution. When a cell can be separated from other cells by a difference in specific gravity of the cell, the cell can be obtained by a velocity sedimentation method. However, when there is substantially no difference among cells in such a case to distinguish an unsensitized cell and a sensitized cell, it is necessary to separate the cells one by one on the basis of information obtained by dyeing them with a fluorescent antibody or information visually obtained by human eyes.
As an example of this technique, there is a cell sorter. Cell sorter is a technique wherein fluorescent dye-treated cells are isolated in one cell unit and dropped into charged droplets, and a high electric field is applied to the charged droplets during the dropping process in any slope plane direction relation to the dropping direction on the basis of the presence or absence of fluorescence on the cells in the droplets and the extent of the amount of light scattering, whereby the dropping direction is controlled so that the cells are fractionized and recovered in a plurality of containers disposed at the bottom (Kamarck, M. E., Methods Enzymol. Vol. 151, pages 150-167(1987)).
However, this technique has many drawbacks that it is expensive and necessitates a large apparatus, a high electric field such as several thousand bolts and a large amount of samples, the cell is possibly damaged in the process of preparing droplets, the sample cannot directly be observed, etc. In these circumstances, a new cell sorter has recently been developed wherein fine particles are separated under direct microscopic observation in a laminar flow passing through fine channels being cut using a micro processing technique (Micro Total Analysis, 98, pp. 77-80 (Kluwer Academic Publishers, 1998); Analytical Chemistry, 70, pp. 1909-1915(1998)). However, this cell sorter has a drawback that the speed of response to observation means when separating a sample is slow. Therefore, it is necessary to develop a cell sorter which does not cause any damage to a sample and can treat a sample in a faster response.
In order to solve such problems, the present inventors have already filed a patent application (Patent Application No. 2002-245902) as for a cell analysis and separation apparatus in which a sample is fractionized using a micro processing technique on the basis of the fine structure of the sample and the distribution of fluorescence in the sample whereby the cell sample can be conveniently separated and recovered without damaging the cell sample.